Fire controlling mechanism for automatic firearms



Dee-9, 1947. e. w. PATCHETT FIRE CONTROLLING MECHANISM FOR AUTOMATIC FIREARMS 2- Sheet-Sheet 1 Filed Nov. 27, 1943 Attorneys Dec. 9, 1947. I I w T 2,432,486

FIRE CONTROLLING MECHANISM FOR AUTOMATIC FIREARMS Filed Nov. 27, 1943 2 Sheets-Sheet 2 m (flnv enlor MLW Attorneys Patented Dec. 9, 1947 FIRE CONTROLLING MECHANISM FOR AUTOMATIC FEREARMS George William Patchett, Chigwell, England Application November 27, 1913, Serial No. 512,004 In Great Britain August 17, 1942 Claims.

' 1 This invention relates to the trigger and firecontrolling mechanism of automatic firearms, and although more particularly applicable to those firearms which fire on the forward stroke of the bolt and in which the bolt recoils against a spring after the cartridge has been fired, it is not necessarily limited to such application.

. In some automatic weapons of the type set forth there is a tendency for the firearm when fitted with a charged magazine to discharge a round involuntarily if subjected to sudden shock,

whilst in use the general balance and control of the weapon may leave much to be desired.

The object sought to be achieved is to overcome the above disadvantages and to render the firearm immune from the liability to discharge a round if subjected to sudden shock, to render the whole of the trigger, sear and fire control mechanism removable as a complete unit for cleaning and adjustment, and to provide a better means whereby the weapon can be placed into a safe, or inoperative condition, or into a semiautomatic or fully automatic condition for use.

This invention consists in the manufacture of an automatic firearm having in combination a trigger operated pivoted sear actuating member, a sear pivoted coaxially with said actuating member pivot, a scar controlling lever pivoted on said sear actuating member, said controlling lever en-- gaging said sear under spring pressure unless displaced about its pivot by a selector device mobile at will to determine the safe or either of two firing conditions.

With the above arrangement the trigger and sear pivots are disposed forward of the bolt and/ or firing pin when the latter are in the cooked position, which arrangement enables a better balance to be given to the weapon and a better functioning of the recoiling masses during the firing operation.

The invention is further characterized that the trigger and sear mechanism are so mounted as to be a readily removable unit, for the purposes of cleaning and adjustment.

To enable the invention to be better understood reference is made to the accompanying drawings wherein a preferred embodiment of the invention is illustrated, and wherein- Fig. 1 is a part sectional vertical elevation of the firearm showing the selector device set at the safe position. I V a Fig. 2'is an enlarged view of the trigger and sel ction mechanism.

Fig. 3 is an end v ew of Fig. 2 from the direction of arrow, line 3-3, Fig. 2.

Fig. 4 shows the removable trigger and sear mechanism as a unit, and the part of the firearm with which the unit is directly associated.

Referring to the drawings and to Figs. 1, 2 and 3 the rifled barrel I is connected to the receiver 2, in which latter is housed a cooking handle 4, the bolt 3 and a firing pin 5. The main recoil spring 6 is held under. compression between the bolt 3 with firing pin 5 and the end cap 1. Beneath the receiver 2 and approximately centrally of its length is the trigger 8. The said trigger is formed with arcuate wiper guards 9 and is pivoted upon a pin 10 mounted in and extending between a pair of trigger plates 28, the said trigger being pressed to its normal or idle position by a spring-loaded plunger H, the latter taking an abutment against a pin or the like l2 extending between two sear actuating plates [5 pivoted on a pin I! carried by the pair of trigger plates 28. The trigger 8 adjacent its pivot pin [0 contacts upon movement with a roller [3 mounted on a pin l3a extending between the sear actuating plates i5. When the said trigger 8 is pulled its face l4 lifts the roller [3, and when released the face l6 of trigger 8 comes to rest in its original position on the roller l3, as shown in Fig. 2. The sear actuating plates l5 are formed as two counterpart cheeks tied and distanced by pillars constituted by stop pin l2, the pivot pin l3a of the roller 13 and other transverse pins or pillars of the mechanism. Between the said sear actuatin plates I5 is disposed the sear l8 on pivot pin [1, having a sear face [8a, a slotted tail piece l8b, a stop We engaging the receiver 2 and a part 18d engaging pivot pin [91) of the sear actuating lever I9. The sear actuating lever I9 is adjacent to the sear and has a cross head 20, said cross head (see Fig. 3) embracing or otherwise guiding the split tail pieces 18b of the sear I 8. The sear I8 is pressed upwards towards the bolt race 2a by a spring-loaded plunger of normal design 2 I. the said plunger contacting with the arm 19a of sear actuating lever IS. The sear is pivoted upon pin ll, this pivot pin and the pivot pin ll] of the trigger 8 being positioned forward of the face 3a of bolt 3 while the bolt is in the cooked position, at which time the forward face of the bolt will occupy the position indicated by the dotted line A in Fig. 1. The scar actuating lever I9 is pivoted between the sear actuating'plates I5 and is provided with a projection 22 adapted to engage the top of the selector cam 23 when the selector. cam is set to safe as shown in dotted lines at B in Fig. 2. The said cam is mounted rigidly upon a mobile shaft 24 and operated by a selector lever 25 disposed on the outside of the gun and aft of, but adjacent to the trigger 8. The selector lever 25 is fast with shaft 26 and by undercutting as at 25b is slightly flexible, and is provided at its terminal 25a remote from shaft 24 with a ball 26, adapted to engage one of three recesses 27 formed in the side plate 35 of the trigger housing. The said recesses 2'! correspond with and control the predetermined angular positions of the selector cam 23, which latter is capable of being set at will to safe at B corresponding to the position of selector lever 25 at S, semi-automatic C corresponding to the position of lever 25 at R and full automatic D corresponding to the position of lever 25 at A in Fig. 4. The total movement of the selector cam 23 is limited by stops 29. The said selector cam 23, at the three determined positions engages respectively: in the safe B position. the projection 22 of the sear actuating lever l9; in semi-automatic C position, the underside of the actuating lever arm Ida; and disengages from any contact with the sear actuating lever I9 when set in D position for full automath or continuous firing.

A removable magazine (not shown) is provided for insertion in the magazine holder 30 (Fig. 4) on receiver 2 and hence is at right angles to the plane of the hand grip 32.

Fig. 4 shows the trigger 8 and associated parts as a removable entity and capable of extraction from the gun by the withdrawal of the locking pins 34 which are removably inserted through trigger plates 28 and a pair of trigger box housing plates 35 fixed to the receiver. In this condition the assembly can be cleaned and replaced in a few minutes.

The operation of the invention is as follows:

Assuming the breech to be closed as shown in Fig. 1 and the selector lever at safe position, i. e. B. Fig. 2, the first action is to set the selector lever 25 to either of the positions C or D and then to cock the bolt 3, by operating the cooking handle or equivalent 4, which causes the bolt and firing pin to traverse backwards until the bolt has passed the sear I8 at position A, Fig. 1. The bolt 3 depresses the sear I 8 at the beginning of its movement backwards, the sear tail piece IBb contacting the pivot pin I9b of the sear actuating lever, thereby causing the sear actuating plates I to pivot about the pin I1, compressing the spring of the plunger II. After the bolt has passed the sear face I8a the spring plunger Ii returns the sear mechanism to position shown in Fig. 2, obstructing the return path of the bolt.

Assuming the selector cam 23 is set to semiautomatic, in position C, the trigger is pulled and its shoulder I4 contacts with the roller I3 rotating the sear actuating plates [5 upon pivot pin I1, which has the eifect of withdrawing the sear face l8a of the sear [8 out of the path of the bolt 3 and causing the sear actuating lever arm I 9a to engage the selector cam 23, as at C. Since further movement downward of said arm IQa is impossible, the sear actuating lever I9 rotates about its pivot pin lfib compressing the spring of plunger 2| and immediately after the sear face I 8a has released the bolt 3, the crosshead'2II disengages from the upper face of the sear tail-piece I81) and releases the sear I8 to pivot on the pin I! under urge of the spring of plunger 2| and regain its original position with the sto I80 engaging the receiver after the bolt has recoiled beyond the cooked position. During this movement and although the crosshead 20 of the sear actuating lever II] has disengaged from the upper face of the sear tail-piece I8b, the said tail-piece I8b still remains in a guided relation to the sear actuating lever I9, since the lower sear parts I 8d still embrace the sear actuating lever I9.

Hence upon such trigger movement the bolt is released by the sear and under urge of the spring 6 moves forward to close the breech and fire the cartridge, which in the forward movement of the bolt has been caused to enter the barrel I, in the known manner. The recoil pressure of firing returns the bolt 3 and striking pin 5 against the pressureof the spring 6, beyond the sear I8, which latter having been released by the crosshead 20 returns to its position akin to that shown in Fig. 2, to arrest the bolt 3 on its then forward movement, even though the trigger is still held back. Hence only a single shot is fired and the bolt is held arrested in the cooked position. During this bolt movement the spent cartridge has been withdrawn by the extractor (not shown) and ejected,

' whilst a new cartridge has been fed forward to the mouth of the magazine, ready to enter the breech of the barrel upon the return of the bolt. So long as the trigger is squeezed nothing further happens, and a single shot only has been fired. If the trigger is released the abutment I4 is withdrawn from the roller [3, the spring plunger II operates to return the sear plates to their original position as shown in Fig. 2, the spring plunger 2i causing the sear actuating lever I9 to also return to its original position, wherein the crosshead 2! gain engages the tail-pieces I8b of the sear I 8. It will be noted that despite the relative motion between the sear actuating plates and the sear the sear actuating lever arm l9 never actually leaves the slotted tail-piece [8b of the sear I8, Re-actuation of the trigger repeats the operation and again a, single shot is fired.

To set the weapon to full continuous automatic firing the selector lever 25 is set so that the selector cam 23 assumes position D, see Fig. 2, and pressure on the trigger 8 will disengage the sear I 8 from the bolt 3 as previously described, but as the downward movement of the sear actuating lever arm [9a is not arrested by the selector cam 23, the crosshead 20 of the sear actuating lever I9 remains in engagement with the sear .tail-piece I81) maintaining the sear below, and

therefore no longer obstructing, the path of the bolt. Hence on actuation of the trigger, the bolt moves forward and fires the cartridge, is driven rearwards by the cartridge recoil, and forwards again by the spring 6, and so on until the trigger is released or the ammunition supply ceases.

If the selector cam 23 be moved to position B, i. e. at safe, while the bolt is uncooked, the sear and associated parts lock the bolt forward as shown in Fig. 1, thus preventing the bolt being jolted back to pick up and fire a cartridge accidentally. If the bolt 3 is cooked and the selector cam 23 then set to safe, the bolt is locked against forward movement by the sear I8 engaging the face 3a of the bolt, nd further the trigger, if pulled, cannot rotate the sear actuating plates I5 owing to the projection 22 of the sear actuating lever I9 contacting the selector cam 23 at position B. Since in these positions the sear is positively locked from all movement, no acci dental shock or olt can displace it, and allow firing. to take place.

It will be observed that the trigger and sear pivots are disposed substantially midway between the limits of operational traverse of the mobile bolt 3.

bolt reciprocable therein, and sear mechanism including a sear actuating member pivotally mounted in the receiver, a sear pivotally mounted in the receiver coaxially of the pivot of said member for holding the bolt in cocked position and retractable to release the bolt, a scar actuating lever pivoted on the sear actuating member eccentrically of the pivotal axis of said member and rotatable into positions to retract the sear from the bolt and to release the sear, means for yieldingly urging said actuating lever into position torelease the sear, a trigger pivoted in the receiver and operative when manually operated to move the sear actuating member and. the sear actuating lever in adirection to retract the sear, the sear actuating 1ever having an arm thereon extending radially from its pivotal axis, and a selector device movable into a position to be engaged by said arm on the sear actuating lever and thereby cause rotation-of the latter on its axis in a direction to release the sear when the sear actuating member is operated by manual operation of the trigger.

2. A firearm comprising a receiver, a breech bolt reciprocable therein, and sear mechanism including a sear actuating member pivotally mounted in the receiver, a sear pivotally mounted in the receiver for holding the bolt in cocked positionand retractable to release the bolt, a trigger pivoted in the receiver and engageable with the sear actuating member to operate the latter when the trigger is manually operated, a lever pivotally mounted on the sear actuating member and rotatable into positions to retract the sear from the bolt and to release the sear, said lever having an arm projecting radially therefrom, means interposed between said arm and the sear for yieldingly urging the sear toward bolt cocking position and said lever toward retracting relation with the sear, and a selector device movable into the path of said arm, when the sear actuating member is operated by manual operation of the trigger, to obstruct said arm and thereby rotate said lever in a direction to release the sear.

3. A firearm comprising a receiver, a breech bolt reciprocable therein, and sear mechanism including a scar actuating member pivotally mounted in the receiver, a sear pivotally mounted in the receiver coaxially of the pivot of said member for holding the bolt in cocked position and retractable to release the' bolt, a trigger pivoted in the receiver and engageable with the sear actuating member to operate the latter in sear retracting direction "when the trigger is manually operated, a lever pivotally mounted on the sear actuating member and having a pair of arms one of which is engageable with the sear to retract it and thereby release the bolt, a spring interposed between the other arm and the sear and acting to urge the sear toward bolt cocking position and the first-mentioned arm into a position to retract the sear, and a selector device movable into a position in the path of said other arm to obstruct its movement and thereby rotate said lever on its pivotal axis in a direction to release the sear when the trigger is manually operated.

4. A firearm comprising a receiver, a breech bolt reciprocable therein, and sear mechanism including a sear actuating member pivotally mounted in the receiver, a sear pivotally mounted coaxially of the pivot of said member for holding the bolt in cocked position and retractable to 6 release the bolt, a trigger pivotally mounted in the receiver and engageable, when manually operated, with said member to operate the latter in a direction to retract the sear and thereby release the bolt, a lever pivotally mounted on the sear actuating member and having a sear retracting arm engageable with and releasable from the other position to obstruct operation of the sear actuating member by the trigger and thereby lock the sear from retraction.

5. An automatic firearm comprising a receiver,

a breech bolt reciprocable therein, a sear pivoted in the receiver for holding the bolt in cocked position and retractable to release the bolt, a sear actuating member pivotally mounted in the receiver, a trigger pivotally mounted in the receiver to engage said member and to operate it in sear retracting direction, a lever having a pivot mounting it on said member, said pivot being engageable with the sear, a sear retracting arm on said lever engageable with the sear and releasable therefrom by rotation of said lever on its pivot, a controlling arm on said lever, a spring between the controlling arm and the sear for urging the latter toward bolt cocking position and urging the lever to rotate on its pivot to engage the sear, and a selector member movable into a position to obstruct movement of the controlling arm and thereby rotate the lever to release the retracting ing the trigger and thereby hold the pivot of said lever against the sear to lock the latter from retraction, and movable into a third position clear of said lever and member and thereby free the sear for retraction by the trigger and hold the sear retracted by said member and lever when the trigger is pulled,

6. An automatic firearm as defined in claim 5, wherein said bolt is provided with means engageable by said sear for retaining the bolt in either its closed or its cocked position, and said selector device when moved into said second position locks said sear in retaining relation with said bolt while the latter is in one or the other of said positions.

7. An automatic firearm as defined in claim 5, wherein said selector device comprises a shaft rotatably mounted in said receiver and carrying an arm movable by rotation of said shaft into difierent angular positions.

8. An automatic firearm comprising a receiver, a breech bolt reciprocable therein, a searpivoted in the receiver for holding the bolt in cocked position and retractableto release the bolt, the sear having a splittail-piece, a sear actuating member pivotally mounted in the receiver, a trigger pivotally mounted in the receiver and operative, when pulled, to engage and move said member in sear retracting direction, a lever pivotally mounted on said member and having a sear retracting arm embraced and guided by the split tail-piece of the scar and engageable with and releasable from said tail-piece by rotation of said lever on its pivotal axis, a controlling arm on said lever, a spring interposed between the controlling arm and thesear' and acting to hold the retracting arm of the lever in retracting relation with the sear and to hold the sear in bolt cocking position, and a selector member movable into the path of said controlling arm, when the sear actuating member is operated by pull of the trigger, to obstruct movement of said controlling arm and thereby cause rotation of said lever on its pivotal aXis to release the sear, said selector member being movable into another position to clear said controlling arm and thereby enable said spring to retain said retracting arm in retracting relation with the sear while the trigger is pulled.

9. A firearm comprising a receiver, a sear pivotally mounted therein, a sear actuating member pivotally mounted in the receiver coaxially with the scar and having a pair of projections thereon located in difierent angular positions around itspivotal axis, means carried by said member for retracting the sear, a trigger pivotally mounted in the receiver and having a recess therein to receive one of said projections, said recess having a wall engageable with the projection therein to move said member in sear retracting direction when the trigger is pulled, said recess having another wall engageable with the projection therein to sto the return movement of the trigger, and a spring interposed between the trigger and the other projection on said member and acting to return the trigger to its normal position and to return the sear to its cocking position.

8 10. A firearm as defined in claim 9, wherein said pro'ection in said recess in the trigger comprises a roller having rolling contact with said walls of said recess.

GEORGE WILLIAM PATCHETT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 512,437 Grifliths et al Jan. 9, 1894 950,576 Paulson Mar. 1, 1910 1,147,906 Swebilius et a1 July 27, 1915 1,293,022 Browning Feb, 4, 1919 1,322,053 Reising Nov. 18, 1919 1,382,058 Bourdelles June 21, 1921 1,382,313 Ortgies June 21, 1921 1,475,761 Fisher Nov. 27, 1923 1,487,722 Coenders Mar. 25, 1924 1,531,044 Sutter Mar. 24, 1925 1,887,690 Lahti Nov. 15, 1932 FOREIGN PATENTS Number Country Date 116,469 Great Britain June 13, 1918 131,931 Great Britain Sept, 11, 191.9 501,265 Germany June 30, 1930 552,560 Great Britain Apr. 14, 1943 555,255 France Mar. 17, 23 

